Increase of melanogenesis by retinoic acid: an ultrastructural and morphometric study.

Melanin is a dark pigment protecting the skin against UV radiation in some organisms. Studies on invasion and metastasis using retinoic acid as inhibitor agent are well known, but its role in melanin production (melanogenesis), especially at ultrastructural level and using morphometry were not well studied. In the present study, we analyzed the effects of retinoic acid on the melanosomes in B16F10 melanoma cells. These organelles were identified and quantified using routine electron microscopy and the specific HMB45 antibody. Other approaches such as immunofluorescence, and flow cytometry were also used. Our results indicated that retinoic acid increased the melanogenesis process in B16F10 melanoma cells. Furthermore, this work also provided evidence that this substance interferes at the subcellular level altering the numerical density of melanosomes, as well as the relative volume of the nucleus and nucleolus. In addition, the cells displayed altered morphology and an increase in the percentage of the relative volume of melanosomes, mainly the stages II-III and IV, leading to melanin formation. Furthermore, a decrease in the cells number after retinoic acid treatment was also observed.

Elective neck dissection versus observation in stage I squamous cell carcinomas of the tongue and floor of the mouth.

A retrospective study was undertaken of patients with T1N0M0 squamous cell carcinoma of the oral tongue and floor of the mouth who underwent surgical treatment between 1985 and 1995. Evaluation of two groups of patients (neck dissection versus observation) was made according to the management of the neck. Results were obtained regarding the presence of occult metastases, recurrence in the neck, treatment failure, results of salvage treatment, and disease-free survival. Forty-nine patients underwent surgical treatment: 25 resection of primary and 24 resection plus neck dissection. Overall incidence of regional metastases was 24.5%. Eight patients (16%) developed recurrence of the disease. Seven (14%) had regional recurrences (including 1 with distant metastases) and 1(2%) had local recurrence. Twenty-four percent of patients from the resection of primary group developed neck recurrences in comparison with 4% of the resection plus neck dissection group (P = 0.05). Overall salvage rate was 37.5%. Second primary tumors developed in 16% of patients. Patients who underwent elective neck dissection had a 23% higher disease-free survival rate compared with those who underwent resection of the tumor alone (P = 0.03). The findings of this study stress the importance of control of the neck in early oral cancer. Elective neck dissection significantly improved regional control of the disease.

Induction and characterization of hypoxanthine-phosphoribosyltransferase (Hprt-) deficient cell lines of Akodon cursor (Rodentia, Sigmodontinae).

Hypoxanthine-phosphoribosyltransferase negative (Hprt-) cell lines derived from an Akodon cursor liposarcoma were obtained by induced mutagenesis. All but one Hprt- cell line lacked Hprt mRNA transcripts while one (AKO 3) coded for a truncated protein. Cell fusion and karyotypic analyses showed that one cell line (AKO 1-15) could be successfully used for constructing hybrid panels and allow for a clear identification of human chromosomes in hybrid cells.

Quantitative analysis of CEA expression in colorectal adenocarcinoma and serum: lack of correlation.

Tissues and sera from 110 patients diagnosed with colorectal primary carcinoma, 20 patients with benign colorectal diseases and 31 healthy donors were subjected to quantitative CEA analysis. Multiple samples from tumor lesions and autologous histologically normal mucosa (10 cm from the tumor) were obtained at the time of surgery (cancer patients) or endoscopy (benign patients and healthy volunteers). CEA content was measured in protein extracts obtained from these tissues using a quantitative RIA method. A limit of normality for CEA content was established as 300 ng/mg of protein. When this was taken as cut-off, 104 of 110 (94.5%) tumor lesions and 51 of 110 (46.4%) autologous histologically normal colonic mucosa from cancer patients had elevated CEA levels. No correlation with stage of disease was found, while a correlation was observed with degree of tumor differentiation. A statistically significant difference between CEA content in tumor lesions and in histologically normal mucosa from cancer patients was observed (p = -0.001). Moreover, CEA content was statistically higher in the normal mucosa from cancer patients than in that from healthy donors (p = 0.005). CEA content in tissue specimens from benign lesions differed significantly from that in tissue from healthy donors (p = 0.005) and in carcinoma lesions (p < 0.001). The highest CEA content was observed in benign lesions with severe dysplasia. No statistical correlation between CEA content in carcinoma tissues and serum CEA levels (r = 0.195, p = .13) was found. Therefore, in considering diagnosis or therapy with anti-CEA MAbs for colorectal-carcinoma patients, or potential therapies with anti-CEA recombinant vaccines, serum CEA levels should not be taken as indicating CEA expression in tumor lesions.

Correlation between tumor-associated glycoprotein 72 mucin levels in tumor and serum of colorectal patients as measured by the quantitative CA 72-4 immunoassay.

Colorectal tissue biopsies were obtained from 110 patients diagnosed with primary colorectal carcinoma (tumor and normal colonic mucosa samples), 20 patients diagnosed with benign colorectal disease, and 31 healthy donors. The level of expression of tumor-associated glycoprotein 72 (TAG-72) was quantitatively measured in each sample using a double-determinant RIA with monoclonal antibodies B72.3 and CC49 and detecting the sialyl-Tn epitope; this assay was termed CA 72-4. Statistical analysis revealed a significant (approximately 10-fold) increase of TAG-72 expression in the colon tumor biopsies when compared with the expression in normal colonic mucosa from the same patients. A regression analysis revealed a significant correlation (r = 0.459; P < 0.001) between TAG-72 levels measured in biopsies from the tumor lesions and those found in the corresponding normal colonic mucosa. Furthermore, regression analysis showed a significant positive correlation between TAG-72 levels in the tumors and sera of the same patients (r = 0.491; P < 0.001). TAG-72 levels in normal colonic mucosa from healthy donors and patients diagnosed with colorectal cancer were compared. TAG-72 expression was 5-fold higher in the normal mucosa from the colorectal carcinoma patients. No relationship between TAG-72 tumor tissue content and stage of disease was found. Moreover, the correlation between TAG-72 distribution and degree of tumor differentiation observed (P < 0.05) was not any more evident when mucinous carcinomas were excluded. Finally, the results provide further evidence that TAG-72 may be considered an important early marker for colorectal cancer and/or other dysplastic colonic diseases. The statistical correlation between TAG-72 levels in tumors and circulating TAG-72 indicates that patients with elevated levels of serum TAG-72, as measured by the CA 72-4 assay, would be most suited for diagnostic and/or therapeutic intervention with the anti-TAG-72 monoclonal antibodies B72.3 or CC49 or vaccine trials using the sialyl-Tn epitope.

TAG-72 expression and its role in the biological evaluation of human colorectal cancer.

Immunohistochemical studies showed that TAG-72 is expressed in more than 80% of colorectal carcinomas, but is rarely expressed in normal epithelium and benign diseases. TAG-72 can also be found in the body fluids of patients with adenocarcinomas, and its direct measurement can be used in conjunction with immunocytochemical analysis to help in discriminating benign from malignant effusions. The evaluation of TAG-72 in serum of colorectal carcinoma patients showed a sensitivity of approximately 40%, comparable to that of the widely used CEA. TAG-72 serum levels correlate with the stage of disease, suggesting its utility in discriminating between early-stage versus late-stage colon carcinoma. Longitudinal studies demonstrated that TAG-72 serum levels may be used as a predictive marker of recurrences. Moreover, the simultaneous measurement of TAG-72 and CEA serum markers improves the monitoring of recurrent disease. Therefore, these data suggest that TAG-72 is a well suitable marker for colorectal cancer.

Clinical utility of CA 72-4 serum marker in the staging and immediate post-surgical management of gastric cancer patients.

CA 72-4 is a high molecular weight, pancarcinoma human tumor mucin which may play an important role in the identification (i.e., staging) and clinical management of patients with gastric carcinoma. In the present study of 242 patients with primary or recurrent gastric cancer, a higher percentage of these patients had measurable serum CA 72-4 levels when compared with either CA 19.9 or CEA. Moreover, the presence of positive serum CA 72-4 levels correlated with the presence of lymph node involvement and with the identification of patients with a poor prognosis due to the presence of an advanced stage of gastric cancer. Post-operative monitoring of serum CA 72-4 revealed that the disappearance of CA 72-4 often indicated curative surgery which correlated with a longer disease-free interval. Additional clinical studies are needed to better evaluate the role of CA 72-4 as a serum marker for human gastric carcinoma. Concomitant studies should also focus on what role CA 72-4 may play in the initiation and/or progression of the gastric carcinoma phenotype.

Biologic evaluation of tumor-associated glycoprotein-72 and carcinoembryonic antigen expression in colorectal cancer, Part I.

Tumor-associated glycoprotein-72 has been recently suggested as a new serum marker for colorectal cancer. In fact, approximately 40 percent of colorectal cancer patients have positive tumor-associated glycoprotein-72 serum levels at the time of diagnosis, while only 3 percent of patients with benign diseases are positive. A longitudinal evaluation of colorectal cancer patients suggested the utility of combining the measurement of tumor-associated glycoprotein-72 with that of carcinoembryonic antigen to monitor disease status not only at the time of diagnosis, but also at the time of recurrence. Several reports have indicated that the expression of some tumor antigens in colorectal adenomas may correlate with those parameters conventionally considered as indicative of malignant transformation. The presence of tumor-associated glycoprotein-72 in colorectal adenomas has been recently correlated with preneoplastic lesions, suggesting that tumor-associated glycoprotein-72 may be considered as an early marker of neoplastic transformation. The evaluation of tumor antigens can be considered a new tool in the management of colorectal cancer.

Establishment of gerbil epidermal cell culture and comparative analysis of the behaviour of these cells with cultured mouse epidermal cells.

The culturing of gerbil epidermal cells is described for the first time. Cells grew first as clumps, formed monolayers of proliferating basal cells and then differentiated, giving rise to a stratified epithelium. To regulate the process of proliferation and differentiation, two kinds of medium were used: the standard one and a low-Ca++ medium. Under these two conditions, cultured gerbil cells were compared with mouse epidermal cell cultures. The cultures maintained in the low-Ca++ medium showed greater differences between the two species, the gerbil epidermal cells displaying a greater proliferative capacity and maintained capacity to differentiate, than did the murine cells. It is believed that this in vitro model may lead to a better understanding of the difference between the two species in vivo, and might explain their differing susceptibility to cutaneous tumour induction.

Myeloid leukemia differentiation by phorbol ester and retinoic acid: a practical approach.

The effects of TPA (12-0-tetradecanoylphorbol-13-acetate) and RA (retinoic acid) were investigated on the cell lines HL60 (acute promyelocytic leukemia) and K562 (erythroleukemia) and on cells from patients with several kinds of leukemia. There were 14 cases of acute lymphocytic leukemia (ALL), 2 cases of chronic lymphocytic leukemia (CLL), 23 cases of acute myeloid leukemia (M1-M7), 5 cases of chronic myelocytic leukemia in blast crisis (CML-BC) and 2 mixed leukemias. In almost all of the cases examined, after TPA exposure cells from patients with proven myeloid leukemia became adherent to the substrate, while lymphoid leukemia cells remained in suspension, allowing the differentiation of lymphoid from myeloid blasts. The only exception was in one case of CLL, which had cells that became adherent with long filamental projections. In addition, increased phagocytosis following TPA exposure permitted characterization of M7 as this was the only myeloid leukemia negative for phagocytosis. Further discrimination between the subtypes of myeloid leukemia could be based on the increased lysozyme production seen after TPA in M4 and M5. Esterase positivity allowed the discrimination of M1 cells, which were negative before and after TPA treatment. In agreement with the results of other authors, TPA and RA led to independent ways of differentiation, granulocytic-like lineage and monocytic-like cells being favored by RA and TPA, respectively. The capacity of the same cell to differentiate into more than one lineage, depending on whether RA or TPA was used, was only seen in the present study with M3 cells.(ABSTRACT TRUNCATED AT 250 WORDS)